The towering waves that pummeled the South Shore on Tuesday dragged a giant red marker in the Ala Wai Channel over the reef and left it lying on near-shore rocks, where it was discovered Wednesday.

"Yesterday was a rare event, not the type of swell we see every year and not in at least several years," said National Weather Service forecaster Tom Birchard.

The roughly 8-foot buoy could be seen bouncing like a cork and was pulled underwater Tuesday in surf at least 15 feet high, and lifeguards had feared it would break free.

Ocean Safety Division Operations Chief Jim Howe said the buoy remained tethered to a concrete block with steel cable.

Though the south swell continued to deflate Wednesday, rescues and warnings were still high in number.

"The numbers indicate that as the swell’s dropping, we’re starting to have less experienced, probably visitors, heading out into the water," Howe said. "The hardest surf size to manage and where we see the most people get into trouble is 6- to 12-foot, not when it’s really big. That’s when we really have to redouble our efforts."

At Waikiki and Ala Moana, lifeguards issued 826 warnings by personal watercraft and made 156 rescues, the city Ocean Safety Division reported.

At west side surf spots that benefit from the southwesterly swell, lifeguards rescued four and issued 390 preventive warnings.

Emergency Medical Services paramedics attended to a few surfers who suffered head cuts Wednesday.

Several surfers suffering from fatigue waved down lifeguards, as did a few surfers with broken boards and snapped leashes.

Then there were those who paddled out when the waves were small, not realizing the waves would grow, then got sucked out and were too scared to come back in, an Ocean Safety official said.

The National Weather Service forecast 8- to 12-foot surf through early this morning, going down to 6 to 8 feet by this afternoon. West-facing shores will be 5 to 8 feet early today, shrinking to 4- to 6-foot heights this afternoon.

"The surf will be down and almost out" by this weekend, Birchard said.

Waves were 6 to 8 feet Wednesday, with some bigger sets on the South Shore, and 4 to 6 feet on the west side, with some bigger sets.

The south swell peaked Tuesday, when waves and sand washed across Farrington Highway near Lahilahi Point in Makaha. Waves as high as 20 feet were reported at Hawaii island’s Isaac Hale Beach and caused some beach erosion at Ahalanui Park.